Conventionally, the sequencing and sorting of biomolecules, and the sorting of cells, is carried out using electrophoresis. A variety of different approaches are possible, but most take a considerable amount of time to run to completion. Furthermore, a balance has to be struck between reading out the results relatively quickly (when the bands will be narrow but very close together) and delaying the readout (in which case the bands, although further apart, will have become broader and more diffuse).